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Intellectual pursuits key to preventing Alzheimer’s disease?

Reading, playing a variety of games, and engaging in other intellectual pursuits on a daily basis over the course of a lifetime could help prevent the formation of amyloid plaques that gunk up the brain and are a hallmark of Alzheimer’s disease. But we may need to get our brains engaged early in life -- years or decades before we start to forget things -- to reap the most benefits.

In the first study of its kind, researchers used positron emission tomography scans to examine the amount of beta amyloid deposits in the brains of healthy seniors with no memory loss, confusion, or other signs of dementia and found that those who reported doing daily brainy activities from the age of six onward had very low levels of amyloid plaque -- on par with of an average person in their early 20s. Those who never or rarely engaged in these activities had higher plaque levels, on average, nearly akin to those with Alzheimer’s disease, according to the study published online today in the Archives of Neurology.

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This could mean that by the time people start to forget where they parked their car or put their keys, it may be too late to prevent further progression of the disease.

“It was fascinating to see that no one who engaged in high levels of cognitive activity had high levels of these plaques,” said study leader Susan Landau, a research scientist at the University of California, Berkeley’s Neuroscience Institute. “We assume many of the healthy people with amyloid plaques will go on to develop Alzheimer’s later on, though the imaging technology hasn’t been around long enough to confirm this.”

While neuroscientists haven’t determined exactly how reading Tolstoy or playing chess might prevent the buildup of amyloid in the brain, previous research indicates that the plaque forms in areas of the brain associated with default behaviors that we do automatically, such as brushing our teeth or driving a car while we’re daydreaming.

“When you learn something new, you need to pay attention to your external world and that leads to decreased activity in the default areas, which could lead to less plaque,” explained Dr. Reisa Sperling, a Brigham and Women’s Hospital Alzheimer’s researcher who was not involved in the study.

Sperling added that the study was small -- involving fewer than 100 participants -- and couldn’t account for certain factors that may have confounded the results, including socioeconomic factors, diet, and overall health behaviors that might also contribute to amyloid plaque formation and Alzheimer’s risk. It also asked participants, whose average age was 76, to recall how much reading, writing, and game-playing they did when they were in elementary school, high school, and as young adults, which Sperling said may have yielded a less than accurate accounting.

“I think it’s a little too early to say that there is a cause and effect relationship, but the finding is intriguing,” Sperling said, and “I definitely think there’s enough data now to encourage” people to make specific lifestyle changes -- the earlier, the better.

Beyond mental calisthenics, getting the body active may lower Alzheimer’s risk. “Most studies suggest you need to engage in vigorous exercise three to four times a week,” said Sperling, “but some have shown walking just a mile a day will have benefits. We don’t know yet if exercise helps those with mild cognitive impairment or if it’s too late by that point.” (The new study didn’t find that those who exercised in the past two weeks had lower plaque levels, but it also didn’t examine exercise habits earlier in life.)

Researchers discovered some time ago that the kinds of learning activities most beneficial for reducing Alzheimer’s risk combine physical activity, social networking, and learning a new skill. Ballroom dance lessons -- or salsa classes for those looking for a modern twist -- fit the bill, said Sperling.

“I think reading is fantastic, but I think the research is a little less clear on doing crossword puzzles or playing video games that don’t involve social interactions.”

Studies have been far more mixed on dietary factors, but Sperling said some have linked a lifelong consumption of dark fruits and vegetables -- such as pomegranates, blueberries, and spinach -- with a lower risk of Alzheimer’s; what’s not known is whether dietary changes later in life also provide this benefit.

Having a low cholesterol level may also be protective, but driving down cholesterol wtih drugs such as statins hasn’t been found to be beneficial.

“I think it’s also clear that there’s a genetic component involved in risk,” said Sperling. “But [genes] could play a much stronger role in those who develop Alzheimer’s before age 65” compared with those who develop it a decade or two later.

Deborah Kotz can be reached at dkotz@globe.com. Follow her on Twitter @debkotz2.
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